Granular product storage



June 1965. J. F. HENDERSON 83 GRANULAR PRODUCT STORAGE Filed Sept. 20,1963 3 Sheets-Sheet 1 59 INVENTOR- dessc' f. Haw-m J1me 1965 J. F.HENDERSON 3,191,783

GRANULAR PRODUCT STORAGE Filed Sept. 20, 1963 3 Sheets-Sheet 2 BY (/5556F/vwaapsow nny/vas- United States Patent C) Texas Filed Sept. 20, 1063,Ser. No. 310,217 1 Claim. (Cl. 214-47) This invention relates to afree-flowing granular product facility in which the product may 'becontinually fed in and out while maintaining substantially uniformproduct size distribution in the stored and reclaimed product.

Since potash sales are more or less seasonal, large storage facilitiesare required by a production facility in order to maintain an even levelof plant production during the peak shipping seasons. Round orrectangular bulildings are common in the industry, with round buildingsbeing 75 to 150 feet in diameter, and rectangular structures from 125 to175 feet wide and up to 650 feet in length. Commonly these buildingshave vertical side Walls up to 15 feet in height, with dome shaped roofsbeginning at the top of the side wall. Finished product is usuallytransported to the top of the structure by conventional conveyor beltsand distributed, in the case of a rectangular building, along the longaxis of the building, to the floor below, which could be a verticaldistance of up to 100 feet.

It is a well known and accepted fact that where dry material containing-a range of mesh sizes falls freely onto a heap of like material,segregation of the mesh sizes occurs in that the coarser fractions tendto roll or travel down the heap along the top surface, so that thelarger components of the material are concentrated in the lowest layersof the heaped material. Since the stored matrial must eventually bereclaimed onto a belt conveyor for transportation to the shippingstation, and since it is mandatory that the reclaimed material consistof the equivalent range of mesh sizes as was in the original material onthe incoming belt conveyor, the particle size segregation becomes aserious problem.

Due to day to day variations in grade and particle size of raw ore asproduced by any mining procedure, the finished material from abeneficiation plant will usually reflect these diiferences in that at acertain time the material may vary slightly in product grade. and screenanalysis from that produced at another time. Consequently, it is ofbenefit to spread the material to be stored as evenly as possible alongthe longitudinal axis of the storage building so that, in effect, thestored material is blended as much as possible with respect to grade andscreen analysis.

Because of the large size of the required storage structures it is noteconomically possible to achieve a substantial live storage. Usually,only 25 to 30% of the material in a filled building can be removeddirectly by a reclaiming system so that 70 to 75% of the materialconstitutes dead storage in that it must be transported to the reclaimdevices by auxiliary means, such as bulldozers and the like.

Due to the present design of box car loading equip ment, the capacity ofreclaim and load-out systems is limited to rates of 250 to 300 tons perhour. Such system-s would not be suitable for larger operationsinvolving of the order of 1,200,000 annual tons.

It is an object of the present invention to provide astorage-reclaim-load-out system which minimizes the problem of mesh sizesegregation.

Another object is to provide such a system which permits thoroughlyblending thestored material for grade control.

An additional object is to drastically reduce the dead storage in thefacility.

A further object is to provide a storage facility in which the reclaimand load-out capacity is at least double that of any other systempresently known.

Briefly, the present invention relates to a storage facility for afreedlowing granular product having a predetermined angle of reposecomprising an elongated storage warehouse defining an enclosed storagearea for said product including an internal elevated endless conveyorbelt means dispose-d lengthwise of said warehouse adjacent the topthereof and along the longitudinal axis thereof. An automaticreciprocally travelling belt-tripping means is coupled with saidconveyor belt means and includes bifurcated funnel means disposed eitherside of said conveyor belt means for uniformly spreading said productlengthwise into said storage area below both sides of said conveyor beltmeans. Product reclaiming means is longitudinally disposed along thebottom of said storage area in substantial alignment with said elevatedconveyor belt means and includes a longitudinally extending vaultedtunnel member having a plurality of oppositely disposed elongatedopenings extending along the length in the upper part thereof adaptedfor communication with the stored product.

A pair of opposed shelf members are disposed along the inside of saidtunnel adjacent the bottom edges of said openings and being ofsufiicient width in relation to the height of said openings toaccomrnodate said granular product at its said angle of repose. A pairof ramps are disposed downwardly at an angle substantially equal to saidangle of repose in the bottom of said storage area on respective sidesof said tunnel and communicate with said openings.

A second endless conveyor belt means is disposed longitudinally of saidtunnel below the level of said shelf members :and rotary plow meansbridges said shelf members and is reciprocally movable along the lengthof said tunnel and has funnel means included therewith communicatingwith said second conveyor belt means. Said rotary plow means is adaptedfor reclaiming the stored product substantially uniformly from saidstorage area and delivering it from said shelf members to the secondconveyor belt means for conveyance externally of said warehouse.

Other objects and features of the invention will become apparent in thefollowing description and claim, and in the drawings in which:

FIG. 1 is a fragmentary elevation of a storage facility according to thepresent invention in partial section;

FIG. 2 is an enlarged fragmentary view in partial section taken alonglines 2--2 of FIG. 1;

FIG. 3 is an enlarged fragmentary view in elevation of the rotary plowmeans andrelated structure;

FIG. 4 is a fragmentary plan view of the rotary plow means; and

FIG. 5 is a fragmentary plan view of a modified arrangement according tothe present invention.

Referring to the drawings, and particularly FIGS. 14 a storage facilityaccording to the present invention is designated generally by referencenumeral 10 and is comprised of an elongated warehouse structure 11having more or less conventional design with bottom vertical side walls12 of approximately 15 feet in height running in straight sections alonga substantial part of the length of the building and merging withrounded end sections 14 (see also FIG. 5). The straight sections may runfor approximately 500 feet or more and the total width may be of theorder of 150 feet. A dome shaped roof 15 rises from the top edge 16 ofsaid walls 12 to enclose the structure to provide a center height of theorder of feet along the axis of the building. Disposed along interiorlighting in the building and natural ventilation.

Conveyor belt-tripping means of conventional design is provided in uppergallery 19 which, as shown schema- -tically in FIG. 1, has upper pulley26 and lower pulley 27 mounted in conjunction with hopper assembly 28for causing conveyor belt 17 to release its conveyed contents 29 beingconveyed into the storage facility on the upper run 30 of the conveyorbelt which moves in the direction of arrow A (see also FIG. 2).

As shown in greater detail in FIG. 2 the belt-tripping means 25 has aframework 31 supported by wheels 32 "on tracks 33 extending for thelength of upper gallery 19 in the top of warehouse 10. Between thetracks is disposed the upper run 3%) of conveyor belt 17 which is causedby pulleys 26, 27 to release conveyed contents 29 into discharge hood 34whereupon the granular product passes downwardly through the angularlegs 35 of bifurcated funnel means 36 where it passes downwardly tolaminated timber arch ribs 37 and is distributed along both sides of theconveyor belt means into the storage 'facility. The gallery may also beprovided with plank decking 38 and hand rails 39 along either side ofthe conveyor belt 17 and belt-tripping means 25 for access by personnelto the upper gallery and its associated equipment.

The belt-tripping means 25 is provided with propulsion means (not shown)which may be either electrical or other motive power as desired so as toautomatically move back and forth along gallery 19 to spread thegranular product 29 substantially uniformly along the length of thefacility.

Disposed longitudinally along the bottom of the storage area insubstantial alignment with the elevated conveyor belt means 17 isproduct reclaiming means 40 comprised of a reclaim tunnel 41 extendingthe length of Warehouse 10, a second endless conveyor belt means 42being supported at its innermost end.43 by pulley 44 and at its; otherend, externally of the tunnel by another pulley (not shown) located, forexample, at a box car loading platform or the like. Conveyor belt 42 hasan upper run 45 and lower run 46 (see also FIG. 2), the former conveyinggranular product 47 in the direction of arrow B to a point external ofthe storage facility 10. Mounted at about the same general level asupper run 45 of the conveyor belt 42 and on either side thereof arerails 48, supported by any conventional or desired supports 49 whichalso constitute the supporting framework for the conveyor belt means 42.Supported on rails 43 and movable therealong on wheels 50 is a productreclaiming apparatus 51 comprising rotary plow member 52 and hopper 53which will be described below.

The floor 54 of warehouse 1t uponwhich rests the stored granular product55 has, at each side of the up- 'wardly extending vaulted roof 56 oftunnel 49, a pair of downwardly extending ramp portions 57 which aredisposed at an angle substantially the same as the angle of 7 repose ofthe granular product being stored. Along either side of tunnel 40 in thevaulted portion 56 thereof are a plurality of oppositely disposed windowmembers or openings 58 which are adjacent ramps 57 for delivering thegranular stored product 55 into'the interior of the tunnel 40 alongopposed shelf members 59 which are disposed along the inside of thetunnel 40 adjacent the bottom edges 60 of openings 58 and being ofsufiicient width in relation to the height of the openings to permit thestored product to extend inwardly along the shelves 59 to achieve itscharacteristic angle of repose thereon.

Reclaiming apparatus 51 is disposed centrally within tunnel 40 betweenshelf members 59 with rotary plow 52 disposed adjacent the respectiveupper surfaces 61 of shelves 59 and having its arcuate plow arms 62extending laterally over substantially the entire width of the shelves59. See also FIGS. 3 and 4.) The reclaiming apparatus 51 is mounted on asuitable base support 63 having wheels 56 resting on and movable alongramp 48 as aforementioned. Disposed centrally beneath rotary plow 52 andbelow the level of shelves 59 is hopper 53- which has an upper mouthportion 64 extending laterally beyond the inner edges 65 of shelves 59to receive the granular product as removed therefrom by plow 52, and abottom portion 66 disposed above the upper run 45 of conveyor belt42,.and of a narrower width than said belt 42 for delivering thereclaimed product 47 thereto.

Suitable motive power is supplied to the wheels 50 by, for example,electric motor 67 and to the plow 52 by, for example, electric motor 68,and by suitable automatic controls (not shown) the reclaiming apparatus51 can be moved continuously back and forth longitudinally of reclaimtunnel 40 to remove the stored product from the warehouse 10.

By the continuous back and forth movement of the belt-tripping means 25in storing the product, and by the reclaiming apparatus 51 in removingthe stored product, substantial uniformity in granular product isachieved.

Due to the nature of the product and the design of the reclaim tunnel 40it is to be understood that a product is removed from shelves 59 byrotary plow 52, additional product flows through access windows 58 fromthe ramps 57 to again achieve its characteristic angular repose on theshelves 59 for further removal upon the return pass of the rotary plow52.

While the above described invention has particular adaptability for usein connection with potash storage and the like it is to be understoodthat it is adaptable for all free-flowing granular materials.

While generally the average angle of repose of potash materials from ausual potash mill is about 40, such angle varies as follows:

Mesh size: Angle of repose (average) 28 x 65 32 14 x 28 36 6 x14 40 Witha storage facility as above described the reclaim and load-out capacityin a typical installation has been found to be from 600 to 800 tons perhourand the dead storage in the building only about 36%.

As shown in FIG. 1 it may be desired to store two or more differentgranular products in the same building such as product X (of a lessercapacity) and product Y. In such instant a transverse divider wall maybe provided at 70 and, whereas one belt-tripping means 25 can beemployed, it is preferable that two rotary plows 52 be provided in thereclaim tunnel 41.

As shown in FIG. 5, for a typical potash plant, two side by sidewarehouse facilities might be deemed necessary, one building for thecoarse product, and the other building for storing a standard productand a smaller granular product. Various combinations are possible.

While certain embodiments of the present invention have been shown anddescribed, it is to be understood that changes and additions may be madeby those skilled in the art without departing from the scope and spiritof the invention.

ping means coupled with said conveyor belt means including bifurcatedfunnel means disposed either side of said conveyor belt means foruniformly spreading said product lengthwise into said storage area belowboth sides of said conveyor belt means, product reclaiming meanslongitudinally disposed along the bottom of said storage area insubstantial alignment with said elevated conveyor belt means including alongitudinally extending vaulted tunnel member having a plurality ofoppositely disposed elongated openings extending along the length in theupper part thereof adapted for communication with the stored product, apair of opposed shelf members disposed along the inside of said tunneladjacent the bottom edges of said openings and being of sufficient widthin relation to the height of said openings to accommodate said granularproduct at its said angle of repose, a pair of ramps disposed downwardlyat an angle substantially equal to said angle of repose in the bottom ofsaid storage area on either side of said tunnel and communicating withsaid openings, a second endless conveyor belt means disposedlongitudinally of said tunnel below the level of said shelf members,rotary plow means bridging said shelf members and reciprocally movablealong the length of said tunnel, funnel means included therewithcommunicatinig with said second conveyor belt means, said rotary plowmeans being adapted for reclaiming the stored product uniformly fromsaid storage area and feeding it from said shelf members to said secondconveyor belt means for conveyance externally of said Warehouse.

References Cited by the Examiner UNITED STATES PATENTS 2,579,153 12/51Meissner 214 16 2,989,171 6/61 Lorenz 21417.82 X

FOREIGN PATENTS 1,076,565 2/ 60 Germany.

HUGO O. SCHULZ, Primary Examiner.

